Dean Arnold wrote:
Jerry D. Hedden wrote:
Conceptually, I think it would require keeping a weak
reference of each private SV associated with a shared SV.
This would need to be done on a per-thread basis. Then when
a thread tries to reference a shared SV, a lookup would be
made to see if a private SV already exists (and still
exists) for that thread. If so, that is returned (and the
ref count of the weak ref is incremented?). If not, a new
private SV is created, and a weak ref to it is appropriately
stored.
Is this a logical approach? If so, is it doable?
For threads::shared, the only solution I can think of is
adding a fieldhash to the thread-private my_ctx structure
keyed by the address of the referent variable's
shared version. Then each attempt to create a new proxy
would lookup any existing persistent proxy for the shared
SV, and return it if found (currently, each new reference
to a shared variable creates a new proxy, which is what causes
this mess).
I forgot one not-so-minor detail: clone processing
would need to be updated to
detect and replace the fieldhash'd proxies, and
update each SV that invoked the magic dup() method
- Dean
